Code animation: Discrete tween with stacking

After building a discrete tween store, it occurred to me that the most common use cases are:

1. The store returns a single value that changes over time based on duration and delay
2. The store maintains a stack of all previous states. It’s like having animated state mutation.
3. The store value is a set, each step in the animation can have a key:, and only the latest value for a key is maintained.

Code

https://svelte.dev/repl/d3ef8bddaca84c0d995282fa526cd264?version=3.38.2

Demo